January Thaw

Temperatures are above freezing this morning everywhere in New England from Caribou in Northern Maine to Bridgeport in southern Connecticut. If you are looking for a period constituting a January thaw, this is certainly a good candidate. We've had a cold month thus far, after a cold November and December. The first 12 days of January will show 8 below normal days and 4 above normal. If we average the days, the month is still turning out to be a cold one.

I hate the term normal or average when it comes to a lot of things, including weather. The idea precipitation and temperature are smooth curves throughout the year is a complete fallacy. The “average” temperatures for today are 36F for a high and 22F for a low. Those numbers are for Logan Airport, but give a good idea of the range for the date. An even less accurate “average” is precipitation. Yesterday’s average precipitation was just over a tenth of an inch. This is calculated by taking dividing the average amount of rainfall for the 30 Januarys between 1981 and 2000 and dividing that number by 31. Our rainfall yesterday was about 5 times higher than average, but is meaningless, because snow and rain are not spread evenly across any month.

In this part of the country the temperature and precipitation are rarely average. Since 2009, there have been 7 January days where the average temperature for the day was, average. Last year there wasn’t one average day in January and this year we haven’t had any either. Another way to look at this is to say out of 133 January days since 2009, only 7 have been “average”.

Yesterday began a stretch of above normal temperatures some of us call a January thaw. Whether this thaw is a real or perceived phenomenon is open to interpretation. Several years ago three meteorologists from Cornell University and the National Weather Service did a study on whether the January Thaw was a “statistical phantom”. The report can be viewed here. It’s quite technical from a statistical standpoint. One part of the conclusion speaks to the absence of a “physical rational” and the “results leave one with little reason to look beyond simple statistical sampling variations as the cause for the January thaw.” Real or perceived, a thaw in January has been part of weather lore for centuries.

Temperatures are going to remain on the milder side of average much of this week before cooling off towards the weekend and beyond the 20th of the month. According to the latest guidance from the computer models, snowfall over the next 10 days looks to be low. I feel more confident about the temperature forecast as opposed to that of precipitation. It takes a much smaller shift in the upper level winds to bring us a rain or snowstorm than it does to vary the temperatures.

This afternoon will feature highs in the 40s and Monday will be even milder with a comfortable reading around 50F in the afternoon. While reading this high are not good for snow lovers or for keeping the ice on the lakes and ponds, they are terrific for saving on heating costs and general piece of mind. A small storm is going to bring rain to the area Tuesday. The cold air will remain locked in Canada during this next event keeping the precipitation in liquid form. There could be some snow showers as the storm ends later Tuesday evening.

If someone comments to you today this weather just isn’t “normal” for January, tell them it certainly is and to just enjoy it. The cold isn’t finished; it’s just taking an atmospheric rest.

After the morning snow, the evening commute will be completed under cloudy skies with no precipitation beyond some light mist or drizzle. The overnight is going to be mainly dry, but some icing can occur simply from the high levels of moisture in the air.

It only takes a few flakes to really foul up a commute. The double entendre is not lost on most of you and this morning was a perfect example. Barely a dusting of snow occurred at the wrong time and another commute became memorable for some of you. If you asked me one of my goals for retirement (years away), it would be to not have to drive on another major highway during a commute to work.

This morning's snow was the first of two weather events over the next couple days. I am looking at the models for the upcoming rain and a couple of things are showing up. First, as the next area of moisture moves northward overnight, a few pockets of freezing drizzle could occur, mostly over northern Worcester County. By Saturday morning, the air will have warmed enough so the threat of any icing will be over.

There is enough concern for freezing rain so an advisory has been issued for areas north and west of Route 495 as well as the about western half of southern New England on a line roughly from Hartford, CT to Worcester, MA. If you are traveling later tonight, be aware of changing road conditions.

As the warmer wind picks up Saturday rain is going to push across the area and while showery at first, this rain is poised to become heavy for the afternoon and evening. There is a lot of tropical moisture riding northward into the system. This means you can expect big puddles on the roads tomorrow evening if you are headed out for a movie or dinner.

If you are going to be at the Patriots game, this is one of those games to bring out the waterproof gear.

The radar image below shows how things are forecast around 7PM tomorrow. Notice the heavy pockets of rain. These areas will continue to pulse northward for the first half of the night bringing copious amounts of rain to the region. I am forecasting 1 to 2 inches of rain with this system.

This amount of rain can cause water issues. Street flooding is almost a definite tomorrow night with the normal susceptible spots likely to flood. Small streams and basements could also see some issue from the heavy rain tomorrow night. There is a flood watch up for areas mostly west of Route 128, but all areas could see issues.

The air is going to be very mild this weekend. Once we rise above freezing later today, most areas will say above this mark through the weekend. Tomorrow highs will easily get into the 50s and with a gusty southerly flow, it’s going to feel like a wet spring day.

Sunday is my pick for the weekend, which should be somewhat obvious after a soaking Saturday. Skies will clear early in the morning leaving us with a bright and sunny sky and mild air. Highs won’t be quite as warm as they will be tomorrow, but still range from 45-52 north to south, not a bad temperature range in mid-January.

Here we go full tilt into winter, well maybe not full tilt yet, but we are headed for big changes. Although this is going to be a small storm, after nearing 60F Monday and now having accumulating snow in the forecast, this will be quite the shock. The front that pushed the warm air out to sea is now south of New England. The problem is that the front, the dividing line between warm and cold air isn't that far away. The two competing air masses are going to spin up a small storm Tuesday night and Wednesday and bring some snow to New England. Right now a general 1-4 inch snowfall is likely. The exceptions to the snow will be the south coast, Cape Cod and perhaps into Boston where the air will too warm for the snow. I'll be updating the forecast and more on Twitter at @growingwisdom

This week, many folks will be talking about the warming trend on the way for tomorrow and continuing right into the weekend. Having such mild air in January is not that unusual nor is it a sign that winter is over. While we have not had a tough winter thus far, this is not last year. Many places in southern New England have seen from half a foot to close to two feet of snow this season. Boston, or more specifically, Logan airport has received just under 4 inches of snow which 75% below what we would expect. Logan sits out in the water and often isn't reflective of the rest of the area. For example, from Newton to Worcester, out to the Berkshires and north into northern New England snowfall is at or above normal for the season thus far. Even Providence, Rhode Island is closing in on a foot of snow for this winter. Let's chat more about the forecast on Twitter at @growingwisdom I also update weather information there regularly.